While conducting the avodah in the Beis Hamikdash, in addition to the 8 garments that made up the Kohen Gadol's uniform, he would also wear his Tefillin.
Why isn't the Tefillin considered a 9th garment?
While conducting the avodah in the Beis Hamikdash, in addition to the 8 garments that made up the Kohen Gadol's uniform, he would also wear his Tefillin.
Why isn't the Tefillin considered a 9th garment?
First of all, tefillin isn't a garment. Second, it's not a garment specifically for the Avodah, so I'm not surprised it's not listed.